A water treatment for cleaning fluid by removing pollutants therefrom may use a heating method, a phase-changing method, or a separation method using a membrane.
The separation method using a membrane has lots of advantages over the method based on heating or phase-changing. Among the advantages is high reliability of water treatment since the water purity required can be easily and stably satisfied by adjusting the size of the pores of a membrane. Furthermore, since the separation method using a membrane does not require a heating process, a membrane can be used with microorganism which is useful for separation process but may be adversely affected by heat.
The separation membrane may include a flat-type membrane, and a hollow fiber membrane. In case of the hollow fiber membrane, there are micro-pores provided on a surface of tubular fiber structure, so that pollutants are filtered through the micro-pores included in the hollow fiber membrane. In comparison to the flat-type membrane, the hollow fiber membrane has the larger surface area owing to its inner and outer surfaces. Accordingly, owing to the advantageous characteristics such as the large surface area of hollow fiber membrane, the hollow fiber membrane is widely utilized for the separation membrane in the recent applications of water treatment.
The hollow fiber membranes, which are manufactured as a predetermined-shaped module, are used for a water treatment field. A related art hollow fiber membrane module will be described as follows.
FIG. 1 is a perspective view illustrating the related art hollow fiber membrane module.
As shown in FIG. 1, the related art hollow fiber membrane module includes a bundle 10 of hollow fiber membranes, and a module case 20.
The bundle 10 of hollow fiber membranes is formed by closely holding plural hollow fiber membranes 11 through the use of potting agent 13. At this time, one end of each of the plural hollow fiber membranes 11 is open so that water permeated through hollows of the hollow fiber membranes 11 is collected inside the module case 20. The potting agent 13 enables to form the bundle 10 by closely holding the plural hollow fiber membranes 11, and simultaneously to pot the bundle 10 of hollow fiber membranes into the inside of the module case 20.
The module case 20 accommodates the bundle 10 of hollow fiber membranes therein, and collects the water permeated through the hollow fiber membranes 11.
However, the related art hollow fiber membrane module is disadvantageous in that the bundle 10 of hollow fiber membranes is apt to be separated from the module case 20 during a module-manufacturing process. In order to pot the bundle 10 of hollow fiber membranes into the inside of the module case 20, the plural hollow fiber membranes 11 are closely held into the bundle 10 through the use of potting agent 13; the bundle 10 of hollow fiber membranes is placed in the module case 20, and is filled with the potting agent 13; and the filled potting agent 13 is hardened. During the hardening process of the potting agent 13, the potting agent 13 might be expanded or shrunken, which cause a reduction of adhesive strength between the bundle 10 of hollow fiber membranes and the module case 20.
Also, the bundle 10 of hollow fiber membranes may be separated from the module case 20 during a water-treatment process. In more detail, if carrying out the water-treatment process through the use of hollow fiber membrane module, the hollow fiber membrane module is submerged in water of a tank for a long period of time. In this case, the adhesive strength between the bundle 10 of hollow fiber membranes and the module case 20 may be reduced due to pressure inside the tank. Especially, when an aeration process for removing pollutants from the hollow fiber membranes 11 is carried out during the water-treatment process, the adhesive strength between the bundle 10 of hollow fiber membranes and the module case 20 may be reduced due to a vibration occurring during the aeration process.
As mentioned above, if the adhesive strength is reduced between the bundle 10 of hollow fiber membranes and the module case 20, the bundle 10 of hollow fiber membranes may be separated from the module case 20, whereby the related art hollow fiber membrane module may malfunction.